Conventionally, in a layout of a semiconductor device (semiconductor chip) which is provided with a switching element such as an Insulated Gate Bipolar Transistor (IGBT) and is used in an igniter, the same structure is adopted in a plane of the semiconductor device, however a current density upon the electric power supply to the semiconductor device is not even in the plane, and unevenness occurs locally. Accordingly, breakdown resistance of the semiconductor device is limited by a portion where the current density becomes high locally, and portions other than the portion where the current density becomes high locally have a margin for the current density (for example, refer to Patent Documents 1, 2).